The present invention relates to the preparation of extracts from olive fruits, olive tree leaves, olive oil as well as olive-press waste, the isolation of natural products from these extracts and the evaluation of the DNA protection ability versus the antioxidant activity of these extracts and the purified compounds on intact mammalian cells.
Olive oil production, which also uses fresh olives, produces as by-products a solid olive mass, often called “pulp”, and wastewater from a water-olive slurry conventionally used in olive oil manufacturing. These olive oil production by-products, are potentially rich in bioactive compounds, but until recently had not been effectively exploited, due to the impracticality of extracting usable amounts of antioxidant compounds using conventional technology. Indeed, although it had been reported that olive oil production wastewater is rich in phenolic antioxidant compounds (Visioli, F., Vinceri, F. F., Galli, C., “Waste waters from olive oil production are rich in natural antioxidants”, Experientia, 1995; 51: 32-34), development of a simple and practical method of extracting such compounds from the wastewater lagged.
European Patent Application No. EP 0 811 678 A1 discloses a process for extracting antioxidants from olives, in which olives are crushed, vacuum dried, and pressed to form a cake. The cake is then extracted with a hot medium chain triglyceride or a C2 to C6 alkylene glycol at a pressure of at least 40 bar, to obtain an antioxidant-enriched extract.
U.S. Pat. No. 6,361,803 to Cuomo et al. discloses obtaining antioxidant compounds by extraction of olive oil or whole olives which have been mashed. This patent also identifies as a problem that several inferior grades of, olive oil used in industrial (rather than culinary) applications, and therefore relatively inexpensive compared to culinary grade olive oil, offer potentially rich sources of antioxidant compounds. To date, however, these potential sources of beneficial antioxidants have not been effectively exploited.
PCT Publication WO 02/18310 describes methods for obtaining a hydroxytyrosol-rich composition from vegetation water comprising acidifying olive wastewater and incubating it, then fractionating to separate hydroxytyrosol.
PCT Publication WO 02/16628 describes methods for the enzymatic synthesis of hydroxytyrosol using a tyrosol precursor.
While a significant portion of the literature discusses the antioxidant properties of hydroxytyrosol and other olive oil isolates, certain olive oil isolates have been somewhat overlooked. In some cases, this phenomenon may be because the isolates appear to have little or no anti-oxidant properties per se (particularly when compared to hydroxytyrosol). An example of such a compound is described by Ford, J. H., et al., “Preparation of calcium elenolate from olive press juice”, Organic Preparations and Procedures International (1972), 4(2), 97-104.
As a result, other, potentially much more valuable, biological properties of certain olive isolates have heretofore gone undetected and unexploited.